Production of bisulphite liquor and cooling carbon dioxide formed therein



Nov. 14, 1933. s. WANG PRODUCTION OF BISULPHITE LIQUOR AND COOLING CARBON DIOXIDE FORMED THEREIN Filed March '6. 1935 G Y T m E mrxm wbmw SOKX M T A W 6 QUMUN\Q\\U$\ w W O J M NW T h l A O 0/, .k M a e o /9 n F G C e0 $4 h l karma c "7 5 W60../ an 1 WW W 9 JJ 6m f C/ c H I h M 2 a O 00 5 q 5 m7 2 CH 2 8/ o w Q m n D s 0 pm G n 0 W s a 3 Mi 5% r M t0 6 t a m 9 2 d o n 0/ 6 o a y Q rmfi w t! z MC J M rfm/a A Z D; Z 0 W 4 Q Patented Nov. 14,1933 Y 7 1 V t PRODUCTION OF-BISULPHITE LIQUORAND .-.-COLING CARBON DIOXIDE FORMED T .THEREIN g Sigmund Wang ".Hawkesbury, Ontario,

Canada a Application March 5, 1933. Serial No. 659,876-

I 6 claims. (01. 23-130) This invention relates to an improved method ates and liberation of carbon dioxide with the of producing bisulphite liquor and cooling the o s q at o o liquora carbon dioxide formed therein preliminary to Car n d ded in the leaetion'tenk liquefaction or solidification of the latter. passes through the Outlet 21 to a washer 22 in a The object of the invention is to-effect econowhich traces of S02 are removed with water .50 mies in the production of these widely u d which enters the reaction chamber at 12. The products, whereby liquid sulphur dioxide, eco- C02 is then deodorized in a purifier 23 from nomically obtainable from smelter gases and the which it s d awn y a a or compressor 24 to a I like, may be employed and brought into'heat exas holder 25.- From this chamber the gas flows change relationship with carbon dioxide, rethrough e heat-exchanger 4 W e it is D leased in the formation of bisulphite liquor, to 0 ed y e 2 from the evaporator and then cool the carbon dioxide preliminary to liqueiacp to the liquefaction p t- Preferably the tion or solidification. p pre-cooled C02 is mixed with CO2 returning from k The invention will be described with reference the drye ma in is a t at ly compressed to the accompanying drawing, in which i and cooledand conveyed through the condenser 7 Figure 1 agrammatically represents a flow 3 to be liquefied or solidified as illustrated.

chart of the process, and g In the production of bisulpllite liquor the ab- Figure 2 is a sectional elevation of thereaction sorption of 500 pounds of S02 liberates substantank. tially 165 pounds of C02 which normally goes 29 Liquid sulphur dioxide, as from a tank car 1, to waste and the present method of utilizing the is led through an evaporator 2, having condenser latent heat of vaporization of the S02 affords a coils or the like 3, to, a heat exchanger 4 and ready method of recovering this C02 and more I preferably througha heater 5 to a gas holder 6 economically producing the bisulphite liquor.

from which the gas is conveyed to a conical reaca The stand-pipe 17 is preferably open at the F tion tank 7, preferably entering the same at the top to permit the escape of any C02 carried by v80 points 8 and 9. t V and freed from the acid. If very strong acid Powdered limestone or dolomite from storage liquor is being made, it may be necessary to con- 10 is fed through a mechanical distributor 11 to nect this outlet'of the stand-pipe with a washer the top of the reaction tank where it meets'to recover S02 which may escape and which I 130 water from the pipes 12, equivalent to the volwould otherwise be lost. The ratio between com 15v ume of raw acid desired. Within the reaction bined and free S02 in the liquor will be regulated tank are located series of perforated baffles 13 by the. amount, of gas admitted to the reaction and 14, through and around which the downchamber in relation-to the water admitted with flowing liquid and rising gases pass. A settling the powdered limestone.

tank 15 is'arranged at the base of the tank andv By the use of the heater 5 the temperature of in communication therewith and has an outlet the evaporated S02 is maintained as required for 16 for the discharge of impurities. A stand-pipe V greatest efliciency in the acid reaction and en- 1'7 communicates with the settling tank and has ables compensation to be made for varying at an overflow outlet 18 which maintains a, constant mospheric temperature conditions in changing liquor level in the reaction tank and leads to'an seasons.

absorption tank 19 which discharges into a stor- W at I c aim is age tank 20. Relief gases from sulphite digesters In p du of bisulphite' qu d may be admitted to the absorption tank as illuscooling o Carbon dioxide eliminal'ye to liquetrated to recover'S02 and strengthen the liquor. faction solidificatiofl of the the process The sulphur dioxide causes-a reaction with the w comprises provl din g an aqueous slu rry of limestone forming bisulphite liquor and liberhmestone el hqmq s f d1o x1de ating carbon dioxide. The rising gases assist the evaporateln. hgat exchange relatlonshlp Wlth, bafiles in creating turbulence in the liquor to m? carbon-11031 de resultmg from the decompo' sitlon of said limestone by means of gaseous sull .malntaln the limestone particles in suspension. dioxidev and reacting gaseous sulphur 5 to the corneal or tapered F the dioxide resulting from such evaporation with the reaction tank, the .undecornposed llmestone ap- Slurry of limestone; preaching the bottom of the a i j ted to 2. In the production of bisulphite liquor and t e action of the Strongest d a d gears, h s condensation of carbon dioxide produced therein,

insuring maximum decomposition of the carbonthe process which comprises providing an aquedioxide to evaporate in repeated heat exchange relationship with the carbon dioxide resulting from the decomposition of said limestone by reaction with gaseous sulphur dioxide and causing the gaseous sulphur dioxide resulting from such evaporation to react with said slurry of limestone.

3. A process as defined in claim 1, wherein the carbon dioxide resulting from said decomposition is washed with water and then deodorized before being brought into heat exchange relationship with said sulphur dioxide. r

4. A process as defined in claim 1, wherein the temperature of the evaporated sulphur dioxide is regulated to compensate for atmospheric temous slurry of limestone, allowing liquid sulphur reaction Zone, adjacent the bottom of which the sulphur dioxide is admitted to insure maximum combination of sulphur dioxide and release of carbon dioxide.

6. A process as defined in claim 1, wherein the carbon dioxide resulting from said decomposition of the limestone is washed with water and wherein said wash water is incorporated with powdered limestone to form said slurry.

SIGMUND WANG. 

